The mathematics scores of American students dropped this year in the U.S. government's National Assessment of Educational Progress, known as the nation's report card. In one Los Angeles school, teachers hope to reverse the decline in grades four and eight with a more interactive approach to the subject.

At El Sereno Middle School, 12-year-old Ethan Jimenez explains to his class how he solved a problem on fractions.

“We call it teamwork math, the student explains, because the whole class works together just to solve problems. Before,” he said, “it used to be one person [working] independently. You couldn't really share your ideas.”

Teachers say the drop in test scores is partly because schools are in transition, with new educational standards known as Common Core. Now in use in most U.S. states, the standards for math and English stress understanding instead of memorizing. Supporters say the new approach helps students grasp mathematics, its abstract principals and its real-world applications.

In another classroom, students are building paper bridges and robots in a program called MESA, which focuses on math, engineering, and science. “They're literally acting as little engineers in our classrooms,” explained teacher Shehnaz Karu. “We empower them with that knowledge, and they literally design, they build, they test, and if it doesn't work, they go back to designing.”

FILE - Sally Kim takes notes during a class in Columbia, Mo. The Common Core approach to math has its critics, who say the method only complicates the subject.

A so-called acceleration center for the Common Core also addresses reading, which program coordinator Betty Kwong said is needed to solve math problems. “The students are able to explain their argument, and explain the argument to another student, and they have a dialogue,” she said.

Collaboration brings a shift from traditional learning methods for teachers as well as students, according to the local district superintendent for schools in East Los Angeles, Frances Gipson.

“It's a different way of preparing our teachers,” said Gipson, “not only in terms of how they work with students, but also how they work with one another as teachers.”

Improving math scores is a challenge, noted Gipson, a former principal of this school. “It's a good challenge,” added El Sereno's current principal, Joyce Dara. “Change is good,” Dara said, “and it helps us all to step up and start to reevaluate the way we address learning and teaching.”

The Common Core approach to math has its critics, who say the method only complicates the subject. Forty-five states and the District of Columbia had adopted the standards, and Indiana, Oklahoma and South Carolina have since repealed them. Last month, the Board of Education in Arizona also rejected them, but the standards remain in place there for now.

At El Sereno Middle School, students and teachers embrace the new approach and say they are working to raise their scores in the next national assessment, which will take place two years from now.